Molder matched the day's best score to set the pace at nine-under 135, with fellow American Alex Prugh, who also shot 66, and Australian Cameron Percy (69) one shot back.

Molder has never won on the PGA tour but victory here at Redstone Golf Club would earn him an invite to next week's US Masters.

"If you tell me not to think about next week, or I'm trying to tell myself, well I'm still thinking about next week," Molder told reporters on Friday. "Put me on top of a building and tell me not to be scared, I'm still going to be scared." Percy admitted he too was thinking about earning a last-minute ticket to the first major of the season.

"Anyone in my position would be thinking about it," he told reporters. "It would be a dream come true to ring up my mates and say 'come over next week.'" Lucas Glover aced the par-three 16th with a six iron, making him the first player to record a hole-in-one since the Houston Open moved to its current venue in 2006. Shortly afterwards, Woody Austin aced No. 7.

Several big names looking to tune-up for the Masters had their preparation shortened by missing the cut.

Among them were Australian Geoff Ogilvy, who double-bogeyed the last hole to bow out, German Martin Kaymer and Northern Irishman Rory McIlroy.

Ernie Els and Phil Mickelson both advanced to the final 36 holes despite frustrating days.

Els shot 74 to fall nine strokes behind, a stroke better than Mickelson, who carded a 76 that included an unusual triple bogey at the 10th.

After pulling his drive into a bush, the lefty took a right-handed swipe at the ball. However, the ball popped out and him on the leg before ricocheting back into the bush.

Mickelson was penalized one stroke for being hit by the ball and decided to take a further one-stroke penalty so that he could drop his ball clear of the bush.